f(x)=√(x^2-2x )+ 2^(x^2-5x+4)
由“x^2-2x ≥0,x^2-5x+4≥0”可得:
x≤0或x≥2,x≥4或x≤1
综合可得:x≤0或x≥4
fmin=f(4)=2√2+1
fmax=f(0)=2^2=4